数组 - 在序列中查找缺失的数字

Question

我正在尝试找到一种简单的方法来循环（迭代）数组以查找序列中所有丢失的数字，该数组看起来有点像下面的那个。

var numArray = [0189459, 0189460, 0189461, 0189463, 0189465];

对于上面的数组，我需要退出 0189462 和 0189464。

更新：这是我从 Soufiane 的回答中使用的确切解决方案。

var numArray = [0189459, 0189460, 0189461, 0189463, 0189465];
var mia= [];

    for(var i = 1; i < numArray.length; i++) 
    {     
        if(numArray[i] - numArray[i-1] != 1) 
        {         
            var x = numArray[i] - numArray[i-1];
            var j = 1;
            while (j<x)
            {
                mia.push(numArray[i-1]+j);
                j++;
            }
        }
    }
alert(mia) // returns [0189462, 0189464]

更新

这是一个使用 .reduce 的更简洁的版本

var numArray = [0189459, 0189460, 0189461, 0189463, 0189466];
var mia = numArray.reduce(function(acc, cur, ind, arr) {
  var diff = cur - arr[ind-1];
  if (diff > 1) {
    var i = 1;
    while (i < diff) {
      acc.push(arr[ind-1]+i);
      i++;
    }
  }
  return acc;
}, []);
console.log(mia);

Answer 1

添加一个类似的方法

1. 找出数组中数字的最小值和最大值
2. 循环使用最大和最小数字以获取完整列表
3. 将完整的数字列表与输入数组进行比较以获得差异

const array = [0189459, 0189460, 0189461, 0189463, 0189465]

const max = Math.max(...array)

const min = Math.min(...array)

let wholeNumber = []

for(var i = min ;i<=max ;i++ ){
  wholeNumber.push(i)
}

const missing = wholeNumber.filter((v)=>!array.includes(v))

console.log('wholeNumber',wholeNumber)

console.log('missingNumber',missing)

Answer 2

这是查找数组中缺失数字的最有效和最简单的方法。只有一个循环，复杂度为 O(n)。

/**
 * 
 * @param {*} item Takes only the sorted array
 */
function getAllMissingNumbers(item) {
  let first = 0;
  let second = 1;
  let currentValue = item[0];
  const container = [];
  while (first < second && item[second]) {
    if ((item[first] + 1) !== item[second]) { // Not in sequence so adds the missing numbers in an array
      if ((currentValue + 1) === item[second]) { // Moves the first & second pointer
        first = second;
        second++;
        currentValue = item[first];
      } else { // Adds the missing number between two number
        container.push(++currentValue);
      }
    } else { // Numbers are in sequence so just moves the first & second pointer
      first = second;
      second++;
      currentValue = item[first];
    }
  }
  return container;
}

console.log(getAllMissingNumbers([0189459, 0189460, 0189461, 0189463, 0189465].sort( (a, b) => a - b )));
console.log(getAllMissingNumbers([-5,2,3,9]));

Answer 3

现在可以使用 find 方法作为单行轻松完成：

const arr = [1,2,3,5,6,7,8,9];

return arr.find((x,i) => arr[i+1]-x > 1) + 1

//4

Answer 4

如下图试试

// Find the missing number
let numArray = [0189459, 0189460, 0189461, 0189463, 0189468];
let numLen = numArray.length;
let actLen = Number(numArray[numLen-1])-Number(numArray[0]);
let  allNumber = [];

for(let i=0; i<=actLen; i++){
  allNumber.push(Number(numArray[0])+i);
}
[...allNumber].forEach(ele=>{
  if(!numArray.includes(ele)){
    console.log('Missing Number -> '+ele);
  }
})

Answer 5

假设没有重复

let numberArray = [];

for (let i = 1; i <= 100; i++) {
  numberArray.push(i);
}
let deletedArray = numberArray.splice(30, 1);
let sortedArray = numberArray.sort((a, b) => a - b);
let array = sortedArray;

function findMissingNumber(arr, sizeOfArray) {
  total = (sizeOfArray * (sizeOfArray + 1)) / 2;
  console.log(total);
  for (i = 0; i < arr.length; i++) {
    total -= arr[i];
  }
  return total;
}

console.log(findMissingNumber(array, 100));

Answer 6

const findMissing = (numarr) => {
  for(let i = 1; i <= numarr.length; i++) {
      if(i - numarr[i-1] !== 0) {
        console.log('found it', i)
        break;
      } else if(i === numarr.length) console.log('found it', numarr.length + 1)
    }
  };

console.log(findMissing([1,2,3,4,5,6,7,8,9,10,11,12,13,14]))

Answer 7

const findMissing = (arr) => {
const min = Math.min(...arr);
const max = Math.max(...arr);
// add missing numbers in the array
let newArr = Array.from(Array(max-min), (v, i) => {
    return i + min
});
// compare the full array with the old missing array
let filter = newArr.filter(i => {
    return !arr.includes(i)
})
return filter;
};

Answer 8

ES6 风格

var arr = [0189459, 0189460, 0189461, 0189463, 0189465]; 
var [min,max] = [Math.min(...arr), Math.max(...arr)];
var out = Array.from(Array(max-min),(v,i)=>i+min).filter(i=>!arr.includes(i));

结果：[189462, 189464]

Answer 9

let missing = [];
let numArray = [3,5,1,8,9,36];
const sortedNumArray = numArray.sort((a, b) => a - b);
sortedNumArray.reduce((acc, current) => {
  let next = acc + 1;
  if (next !== current) {
    for(next; next < current; next++) {
      missing.push(next);
    }
  }
  return current;
});

Answer 10

请检查以下代码.....

function solution(A) {
   var max = Math.max.apply(Math, A);
   if(A.indexOf(1)<0) return 1;
   var t = (max*(max+1)/2) - A.reduce(function(a,b){return a+b});
   return t>0?t:max+1;
}

Answer 11

function missingNum(nums){
    const numberArray = nums.sort((num1, num2)=>{
      return num1 - num2;
   });
   for (let i=0; i < numberArray.length; i++){
      if(i !== numberArray[i]){
        return i;
      }
   }
 }
 console.log(missingNum([0,3,5,8,4,6,1,9,7]))

Answer 12

要在一个序列中找到一个缺失的数字，首先，我们需要对一个数组进行排序。然后我们可以确定缺少哪个数字。我在这里提供了带有一些测试场景的完整代码。此代码将仅识别缺少的正数，如果您传递负值，即使它给出正数。

function findMissingNumber(inputAr) {
  // Sort array
  sortArray(inputAr);

  // finding missing number here
  var result = 0;
  if (inputAr[0] > 1 || inputAr[inputAr.length - 1] < 1) {
    result = 1;
  } else {
    for (var i = 0; i < inputAr.length; i++) {
      if ((inputAr[i + 1] - inputAr[i]) > 1) {
        result = inputAr[i] + 1;
      }
    }
  }
  if (!result) {
    result = inputAr[inputAr.length - 1] + 1;
  }
  return result;
}

function sortArray(inputAr) {
  var temp;
  for (var i = 0; i < inputAr.length; i++) {
    for (var j = i + 1; j < inputAr.length; j++) {
      if (inputAr[j] < inputAr[i]) {
        temp = inputAr[j];
        inputAr[j] = inputAr[i];
        inputAr[i] = temp;
      }
    }
  }
}

console.log(findMissingNumber([1, 3, 6, 4, 1, 2]));
console.log(findMissingNumber([1, 2, 3]));
console.log(findMissingNumber([85]));
console.log(findMissingNumber([86, 85]));
console.log(findMissingNumber([0, 1000]));

Answer 13

这是@Mark Walters 的function 的变体，它增加了为序列指定下边界的功能，例如，如果您知道序列应该始终以0189455 或其他一些数字（如1）开始.

也应该可以调整此代码以检查上边界，但目前它只能寻找下边界。

//Our first example array.
var numArray = [0189459, 0189460, 0189461, 0189463, 0189465];
//For this array the lowerBoundary will be 0189455
var numArrayLowerBoundary = 0189455;

//Our second example array.
var simpleArray = [3, 5, 6, 7, 8, 10, 11, 13];
//For this Array the lower boundary will be 1
var simpleArrayLowerBoundary = 1;

//Build a html string so we can show our results nicely in a div
var html = "numArray = [0189459, 0189460, 0189461, 0189463, 0189465]<br>"
html += "Its  lowerBoundary is \"0189455\"<br>"
html += "The following numbers are missing from the numArray:<br>"
html += findMissingNumbers(numArray, numArrayLowerBoundary);
html += "<br><br>"
html += "simpleArray = [3, 5, 6, 7, 8, 10, 11, 13]<br>"
html += "Its  lowerBoundary is \"1\".<br>"
html += "The following numbers are missing from the simpleArray:<br>"
html += findMissingNumbers(simpleArray, simpleArrayLowerBoundary);

//Display the results in a div
document.getElementById("log").innerHTML=html;

//This is the function used to find missing numbers!
//Copy/paste this if you just want the function and don't need the demo code.
function findMissingNumbers(arrSequence, lowerBoundary) {
  var mia = [];
  for (var i = 0; i < arrSequence.length; i++) {
    if (i === 0) {
      //If the first thing in the array isn't exactly
      //equal to the lowerBoundary...
      if (arrSequence[i] !== lowerBoundary) {
        //Count up from lowerBoundary, incrementing 1
        //each time, until we reach the
        //value one less than the first thing in the array.
        var x = arrSequence[i];
        var j = lowerBoundary;
        while (j < x) {
          mia.push(j); //Add each "missing" number to the array
          j++;
        }
      } //end if
    } else {
      //If the difference between two array indexes is not
      //exactly 1 there are one or more numbers missing from this sequence.
      if (arrSequence[i] - arrSequence[i - 1] !== 1) {
        //List the missing numbers by adding 1 to the value
        //of the previous array index x times.
        //x is the size of the "gap" i.e. the number of missing numbers
        //in this sequence.      
        var x = arrSequence[i] - arrSequence[i - 1];
        var j = 1;
        while (j < x) {
          mia.push(arrSequence[i - 1] + j); //Add each "missing" num to the array
          j++;
        }
      } //end if
    } //end else
  } //end for
  //Returns any missing numbers, assuming that lowerBoundary is the
  //intended first number in the sequence.
  return mia;
}

<div id="log"></div> <!-- Just used to display the demo code -->

Answer 14

我为此使用递归函数。

function findMissing(arr, start, stop) {

    var current = start,
        next = stop,
        collector = new Array();

    function parseMissing(a, key) {
        if(key+1 == a.length) return;

        current = a[key];
        next = a[key + 1];

        if(next - current !== 1) {
            collector.push(current + 1);
            // insert current+1 at key+1
            a = a.slice( 0, key+1 ).concat( current+1 ).concat( a.slice( key +1 ) );
            return parseMissing(a, key+1);
        }

        return parseMissing(a, key+1);
    }

    parseMissing(arr, 0);
    return collector;
}

如果您正在查看大量数字，这不是最好的主意。公平警告：递归函数是资源密集型的（指针和东西），如果您处理大量数字，这可能会给您带来意想不到的结果。你可以看到jsfiddle。这也假设您已对数组进行了排序。

基本上，您将要使用的数组、起始编号和终止编号传递给“findMissing()”函数，然后让它从那里开始。

所以：

var missingArr = findMissing(sequenceArr, 1, 10);

Answer 15

注意你的前导零，当数组被解释时它们将被删除-

var A= [0189459, 0189460, 0189461, 0189463, 0189465]

（A 返回 [189459,189460,189461,189463,189465]）

function absent(arr){
    var mia= [], min= Math.min.apply('',arr), max= Math.max.apply('',arr);
    while(min<max){
        if(arr.indexOf(++min)== -1) mia.push(min);
    }
    return mia;
}

var A= [0189459, 0189460, 0189461, 0189463, 0189465]; 警报（缺席（A））

/* 返回值：（数组） 189462,189464 */

Answer 16

对数组进行排序会相当简单：

numArray.sort();

然后，取决于对您来说最简单的方法：

1. 您可以只遍历数组，捕捉顺序模式并随时检查它们。
2. 您可以将数组拆分为多个序列号数组，然后检查每个单独的数组。
3. 您可以将排序后的数组简化为一个对数组，其中每对都是开始和结束序列，然后将这些序列开始/结束与您的其他数据进行比较。

Answer 17

如果你知道数字是有序且递增的：

for(var i = 1; i < numArray.length; i++) {
    if(numArray[i] - numArray[i-1] != 1) {
           //Not consecutive sequence, here you can break or do whatever you want
    }
}